I doubted Loki was really dead for good because the death scene and aftermath was not prolonged enough, for a major character. I was also doubtful of lasting redemption, dead or not. I certainly didn't expect the end, but I thought it was a marvellous way to continue Loki's trickster, wildcard-morality character arc and further complicate Thor and Loki's relationship which must not "freeze" as someone else put it, because it's a cornerstone of their appearances together, must keep fresh and tell a progressive story, and also from what Feige is saying, he realises Loki is a very popular character.

There's a lot of ways to go from here with that end; it's certainly sparked my imagination and I think that of many. I see those hoping for redemption for Loki are a bit upset right now, lol.